While providing means for the escape of products of combustion from an associated fireplace, the flue of a chimney also presents an opening for the undesirable admission of rain, sheet, snow, insects, animals, and birds to the associated fireplace. In addition, significant heat loss occurs through the flue of a chimney when there is no fire in the fireplace.
Accordingly, it has been found highly desirable to provide damper means to close off the flue when there is no fire in the fireplace. Various means are known for closing the flue of the chimney when the fireplace is not in use including the well known firebox damper has been used extensively and other prior arrangements as illustrated in U.S. Pat. Nos. 2,704,502, 2,856,839, 3,267,832 are well know in the art.
In addition U.S. Pat. No. 3,945,307 Lyemance, shows a normally open damper arrangement to be located at the floor outlet which includes a sealing arrangement to prevent leakage of rain or snow into the chimney. Further, the seal reduces heat loss from the chimney.
U.S. Pat. No. 4,165,679 Lyemance provides one improvement on the structure of U.S. Pat. No. 3,945,307 and the present invention provides further improvement of the structure taught in U.S. Pat. No. 4,165,679.
Most previous arrangements, other than the aforenoted Lyemance arrangements, have allowed wind blow rain to enter a flue even through the damper located at the top of the flue has been closed. Further, in most prior art arrangements the damper is normally closed and is opened to allow the use of the flue, contrary to the present invention. In the event a fire is built in the fireplace without opening the damper the building associated with the fireplace is filled with smoke.
While devices in accordance with the Lynemance teachings was satisfactorily the present invention further improves the operation of such devices and particularly the opening of such devices when stuck closed.